298 Phelps and Eddy — Ester 'Formation. 



set free. The commercially pure chlorides of copper, barium, 

 and strontium were made anhydrous by drying in an air-bath 

 at 100°. Hydrous aluminium* chloride was prepared by 

 precipitating the commercial salt in water solution with hydro- 

 chloric acid gas and drying the product in a desiccator. Lead 

 chloride was made by recrystallizing and drying in a desiccator 

 the product obtained by precipitating pure lead nitrate with 

 hydrochloric acid. In case of all the other chlorides, the 

 preparation of which is not given, the commercially pure 

 material was used. The various chlorides were used in such 

 molecular ratio that the chlorine should be present in the same 

 amount as in the experiments with zinc chloride, which have 

 been published previously. 



The procedure is the same as has been given in the earlier 

 work to which reference has been made. In the experiments 

 alcohol, with hydrochloric acid in the concentrations indicated 

 in the tables, was driven over as vapor from a 500 cm3 round- 

 bottomed flask into the mixture of benzoic acid and alcoholic 

 hydrochloric acid containing the additional catalyzer in a 

 second 500 cm3 round-bottomed flask carrying a modified Hem- 

 pel column through which vapors passed to a condenser. The 

 temperature of the second flask was kept between 100° and 

 110°. 



In most cases the crude ester from the esterification was 

 recovered by extraction with ether in the manner outlined in 

 earlier work on catalysis in ester formation. Where on 

 account of a large amount of such catalyzers as bismuth, anti- 

 mony, or tin chloride, an ether extraction would be impracti- 

 cable, the mass of ester with the low-boiling products was 

 distilled from the esterification flask to a 100 cm3 Claisen flask 

 before neutralizing with potassium carbonate and recovering 

 by the proceduref jDublished by us earlier in this Journal. 



It is evident from an inspection of the results given in the 

 tables that, as has been seen in all the previous work on 

 esterification, the amount of ester formed, other conditions 

 remaining the same, varies with the kind and amount of the 

 catalyzers present, with the time of action, and with the quan- 

 tity of alcohol. Certain of the catalyzers appeared under the 

 conditions of experimentation to dissolve completely in the 

 alcoholic mixture. This was observed in the use of the chlor- 

 ides of zinc, lithium and tin. In the cases of the chorides of 

 copper, calcium and mercury in the higher condition the smaller 

 amounts only seemed to go into solution completely. Alumin- 

 ium chloride in the smaller amount used went into solution at 

 first but later in the experiment was precipitated out. The 



* Gooch and Havens, this Journal, ii, 416. f This Journal, xxvi, 253. 



